European patent application EP-A-0 612 618 describes a coating circulation and wash-up system for printing presses. Here, a metering device consists of a chambered doctor blade with an applicator roller that engages with a plate cylinder (rubber blanket cylinder). A supply line and a return line that are coupled to a reservoir for a coating liquid, for example, a coating composition, are associated with the metering device. The supply line and the return line have pumps upstream and downstream from the metering device, especially peristaltic pumps, that ensure the supply and return of the coating liquid. A first switch-over valve is installed in the supply line for the coating liquid and is also coupled on the line side to a reservoir to hold water that can be heated if necessary. A second switch-over valve is installed in the return line for the coating liquid and is also coupled on the line side to a reservoir to hold waste. The metering device can be switched over by means of valves, so that it can be supplied with either ink or water (for purposes of washing the device).
German utility model DE 200 12 101 U1 describes an ink supply and washing device for a printing machine. The device preferably comprises ink circulation pumps that pump the ink from ink reservoirs on the line side to the inking unit of the printing machine and back again. For special coating applications, the coating composition can be cooled or heated by means of a heat exchanger. Following the coating process, switch-over valves can be employed to flush and clean the coating circulation system with washing water (cleaning liquid). The components of the device are controlled, regulated and monitored centrally by a control module.
The publication titled KBA-Process, no. 3, edition January/2006, pages 32 to 35, describes variants of inline coating. According to this publication, a coating tower has two separate coating circulation systems that can be switched over between two types of coating compositions. Optionally, a fully automatic and self-cleaning coating supply system for dispersion coatings and UV coatings can be connected. Here, the coating composition in question is conveyed through an aggregate for conditioning it before it reaches the metering device, in this case a chambered doctor blade. Publisher: Koenig & Bauer AG, Marketing Department, Friedrich-Koenig-Str. 4, 97080 Würzburg, Germany; Internet address as of May 2, 2007: www.kba-print.de/de/news/presseservice/download_kba_process.html.
U.S. Pat. No. 5,520,739 describes an assembly for coating a surface in a printing process which, from a reservoir containing a single aqueous coating formulation, supplies a coating composition for various systems in order to feed the coating compositions to printing processes. The device for feeding the coating compositions is described as a reactor vessel in which the temperature and thus the viscosity of the coating composition can be influenced. For this purpose, the reactor vessel is provided with a heat exchanger, a temperature sensor as well as a viscometer to establish the pre-determined viscosity of the coating composition. The composition can only be influenced shortly before the coating process. The physical conditions between the reactor vessel and the coating process are not taken into account.